Extension authoring: List useful node modules

[aeschli]

We have a bunch of node modules written by us to help writing VSCode extensions. We should list them for other extension authors.

• vscode-nls - Support for externalization and localization

• vscode-uri - URI implementation that is used by VS Code and its extensions

• jsonc-parser - scanner and fault tolerant parser to process JSON with or without comments

• request-light - light weight nodejs request library with proxy support

• vscode-extension-telemetry - consistent telemetry reporting for VSCode extensions

• vscode-languageclient - easily integrate language servers adhering to the language server protocol